<template>
    <div class="shopcart">
      <div class="content">
        <div class="content-left">
          <div class="logo-wrapper">
            <div class="logo" :class="{'highlight':totalCount>0}">
              <i class="icon-shopping_cart" :class="{'highlight':totalCount>0}"></i>
            </div>
            <!--购买的商品总数量-->
            <div class="num" v-show="totalCount>0">
              {{totalCount}}
            </div>
          </div>
          <div class="price" :class="{'highlight':totalCount>0}">￥{{totalPrice}}</div>
          <div class="desc">另需配送费￥{{deliveryPrice}}元</div>
        </div>
        <div class="content-right">
          <div class="pay" :class="payClass">
            {{payDesc}}
          </div>
        </div>
      </div>
      <!--购物车小球-->
      <div class="ball-container">
        <transition-group name="drop"
                          v-on:before-enter="beforeEnter"
                          v-on:enter="enter"
                          v-on:after-enter="afterEnter">
          <div v-for="(ball,index) in balls" v-show="ball.show" class="ball" :key="index">
            <div class="inner inner-hook" :key="index"></div>
          </div>
        </transition-group>
      </div>
    </div>
</template>

<script type="text/ecmascript-6">
    export default {
        props: {
          selectFoods: {
            type: Array,
            default() {
              return []
            }
          },
          deliveryPrice: {
            type: Number,
            default: 0
          },
          minPrice: {
            type: Number,
            default: 0
          }
        },
        data () {
          return {
            balls: [
              {
                show: false
              },
              {
                show: false
              },
              {
                show: false
              },
              {
                show: false
              },
              {
                show: false
              }
            ],
            dropBalls: []
          }
        },
      computed: {
          totalPrice () {  //计算购物车的实时总价
            let total = 0
            this.selectFoods.forEach((food) => {
              total += food.price * food.count
            })
            return total
          },
        totalCount () { // 商品的综合
            let count = 0
          this.selectFoods.forEach((food) => {
            count += food.count
          })
          return count
        },
        payDesc () {
            if (this.totalPrice === 0) {
              return `￥${this.minPrice}元起送`
            }else if(this.totalPrice < this.minPrice) {
              let diff = this.minPrice - this.totalPrice
              return `还差￥${diff}元起送`
            }else {
              return '去结算'
            }
        },
        payClass() {
            if (this.totalPrice<this.minPrice) {
              return 'not-enough'
            }else {
              return 'enough'
            }
        }
      },
      methods: {
          drop (el) {
            for (let i = 0; i < this.balls.length; i++) {
              let ball = this.balls[i]
              if (!ball.show) {
                ball.show = true
                ball.el = el
                this.dropBalls.push(ball)
                return
              }
            }
            // console.log(el)
          },
        beforeEnter (el) {
          //el元素表示小球的div，ball.el表示加按钮
          let count = this.balls.length
          while (count--) {
            let ball = this.balls[count]
            if (ball.show) {
              let rect = ball.el.getBoundingClientRect()
              let x = rect.left - 32
              let y = -(window.innerHeight - rect.top - 22)
              el.style.display = ''
              el.style.webkitTransform = `translate3d(0,${y}px,0)`
              el.style.transform = `translate3d(0,${y}px,0)`
              let inner = el.getElementsByClassName('inner-hook')[0]
              inner.style.webkitTransform = `translate3d(${x}px,0,0)`
              inner.style.transform = `translate3d(${x}px,0,0)`
            }
          }
        },
        enter (el) {
          /* eslint-disable no-unused-vars */
          let rf = el.offsetHeight
          this.$nextTick(() => {
            el.style.webkitTransform = 'translate3d(0,0,0)'
            el.style.transform = 'translate3d(0,0,0)'
            let inner = el.getElementsByClassName('inner-hook')[0]
            inner.style.webkitTransform = 'translate3d(0,0,0)'
            inner.style.transform = 'translate3d(0,0,0)'
          })
        },
        afterEnter (el) {
          let ball = this.dropBalls.shift()
          if (ball) {
            ball.show = false
            el.style.display = 'none'
          }
        }
      }
    }
</script>

<style lang="stylus" rel="stylesheet/stylus">
  .shopcart
    position: fixed
    left: 0
    bottom: 0
    z-index: 50
    width: 100%
    height: 48px
    .content
      display: flex
      background: #141d27
      font-size: 0
      color: rgba(255,255,255,0.4)
      .content-left
        flex: 1
        .logo-wrapper
          display: inline-block
          vertical-align: top
          position: relative
          top: -10px
          margin: 0 12px
          padding: 6px
          width: 56px
          height: 56px
          box-sizing: border-box
          border-radius: 50%
          background: #141d27
          .logo
            width: 100%
            height: 100%
            border-radius: 50%
            text-align: center
            background: #2b343c
            &.highlight
              background: rgb(0,160,220)
            .icon-shopping_cart
              line-height: 44px
              font-size: 24px
              color: #80858a
              &.highlight
                color: #fff
           .num
             position: absolute
             top: 0
             right: 0
             width: 24px
             height: 16px
             line-height: 16px
             text-align: center
             border-radius: 16px
             font-size: 9px
             font-weight: 700
             color: #fff
             background: rgb(240,20,20)
             box-shadow: 0 4px 8px 0 rgba(0,0,0,0.4)
        .price
          display: inline-block
          vertical-align: top
          margin-top: 12px
          line-height: 24px
          padding-right: 12px
          box-sizing: border-box
          border-right: 1px solid rgba(255,255,255,0.1)
          font-size: 16px
          font-weight: 700
          &.highlight
            color: #fff
        .desc
          display: inline-block
          vertical-align: top
          margin: 12px 0 0 12px
          line-height: 24px
          font-size: 10px
      .content-right
        flex: 0 0 105px
        width: 105px
        .pay
          height: 48px
          line-height: 48px
          text-align: center
          font-size: 12px
          font-weight: 700
          background: #2b333b
          &.not-enough
            background: #2b333b
          &.enough
            background: #00b43c
            color: #fff
    .ball-container
      .ball
        position: fixed
        left: 32px
        bottom: 22px
        z-index: 200
        &.drop-enter-active, &.drop-leave-active
          transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41)
          .inner
            width: 16px
            height: 16px
            border-radius: 50%
            background: rgb(0,160,220)
            transition: all 0.4s linear

</style>
